In the communication of data and/or other types of communication traffic, various technologies have been used. For over a hundred years, copper connections between a Central Office (CO) and customers have been sufficient. The evolution of Digital Subscriber Line (DSL) technology, which boosts the data performance of the copper-based last mile, has allowed operators to use their legacy networks to offer high-speed Internet access of speeds between 8 Mbps and 16 Mbps. This bandwidth will likely not be enough to support emerging Internet applications, particularly in markets where demand for High-Definition TV (HDTV) and interactive applications increases. If customers demand more bandwidth than what an all-copper-based last mile can deliver, other network architectures will need to be considered.
In some architectures, there are situations in which a sending device or system receives traffic that it originally sent, which can potentially cause problems.